Allen,
I'll suggest that you are wrong in your interpretation of ABS brake system
operation.
A well-respected source of automotive systems is "Auto Service and Repair" by
Stockel & Stockel. A few quotes if I may,
"One of the most common body computer systems found on vehicles today is
the
anti-lock brake systems. .... Most anti-lock brake systems contain ... wheel
speed sensor units, an anti-lock control module, and a hydraulic actuator. ...
The anti-lock control module uses the sugnals produced by the sensors to
determine when the anti-lock system should be activated. When a wheel is nearing
a lockup condition, the control module signals the hydraulic actuator to
regulate
fluid pressure to the wheel...."
There's much more along those lines. ABS prevents lock-up. It's a great
system, in theory, but computers and sensors aren't always at optimum. I just
suggest that folks with ABS should give them a try under controlled conditions
so
as not to be surprised, as I was.
Bud Krueger
Ajhsys@aol.com wrote:
> In a message dated 01/19/2000 7:02:04 PM Eastern Standard Time,
> bkrueger@ici.net writes:
>
> << The ABS would not allow the brakes to come anywhere near locking up. The
> pedal
> was against the stop and the car just wasn't stopping. There was no pulsing
> going on at all. Remember, the action of ABS is to relieve braking pressure
> when the system senses that the brakes are about to lock up. >>
>
> - - - - - - - - - - - - - - - - - - - - - - -
>
> As I understand it, ABS relieves pressure in the brakes lines AFTER the
> wheels lock up. There are wheel sensors that read the speed of the wheel,
> and if it stops, the ABS pump dumps some of the pressure to keep the wheel
> turning. Some cars have sensors on all four wheels, some on just tow, and I
> think there are some three channel ABS systems, probably two in front and one
> for both rears.
>
> You should have felt the ABS pulsing the brakes. If not, there was something
> wrong with the pump and you should have seen a warning light.
>
> The speed sensors are similar to the ones we use for rally computers. Some
> rallyists even connect the ABS sensors to their computers.
>
> Also, be aware that the ABS pump requires a brake fluid that keeps it
> lubricated. Do not use DOT 5 silicone brake fluid with ABS.
>
> Allen Hefner
> Philly Region SCCA Rally Steward
> '77 Midget
> '92 Mitsubishi Expo LRV Sport
--
Bud Krueger
http://home.ici.net/~bkrueger/
52TD
77MGB
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